# Phase 3: Localization (EN/RU)

**Status:** ⬜ Not Started
**Parent plan:** [PLAN.md](./PLAN.md)
**Domain:** fullstack

## Objective
Add internationalization (i18n) support with English and Russian locales. All UI strings should be translatable. Users can switch language in settings or header.

## Tasks

- [ ] Task 1: Install `paraglide-sveltekit` (or `svelte-i18n`) — choose the best Svelte 5 compatible i18n library
- [ ] Task 2: Create locale files: `src/lib/i18n/en.json` and `src/lib/i18n/ru.json`
- [ ] Task 3: Create `src/lib/i18n/index.ts` — i18n setup, locale detection, switcher
- [ ] Task 4: Create `src/lib/components/layout/LanguageSwitcher.svelte` — language toggle (EN/RU) in header
- [ ] Task 5: Extract all hardcoded strings from layout components (Sidebar, Header, MainLayout)
- [ ] Task 6: Extract all hardcoded strings from auth pages (login, register, logout)
- [ ] Task 7: Extract all hardcoded strings from board/section/widget components
- [ ] Task 8: Extract all hardcoded strings from app components (AppCard, AppForm, AppIconPicker, etc.)
- [ ] Task 9: Extract all hardcoded strings from admin pages (users, groups, settings)
- [ ] Task 10: Extract all hardcoded strings from search components
- [ ] Task 11: Add locale preference to user settings (stored in localStorage + optional DB field)
- [ ] Task 12: Add language setting to admin SystemSettings (default locale)
- [ ] Task 13: Translate all strings to Russian

## Files to Modify/Create
- `src/lib/i18n/en.json` — NEW
- `src/lib/i18n/ru.json` — NEW
- `src/lib/i18n/index.ts` — NEW
- `src/lib/components/layout/LanguageSwitcher.svelte` — NEW
- `src/lib/components/layout/Header.svelte` — MODIFY
- `src/routes/login/+page.svelte` — MODIFY
- `src/routes/register/+page.svelte` — MODIFY
- `src/routes/boards/*.svelte` — MODIFY
- `src/routes/apps/+page.svelte` — MODIFY
- `src/routes/admin/**/*.svelte` — MODIFY
- `src/lib/components/**/*.svelte` — MODIFY (all UI components)

## Acceptance Criteria
- All user-visible strings are translatable (no hardcoded text in components)
- English and Russian translations are complete
- Language switcher in the header toggles between EN/RU
- Locale preference persists across sessions (localStorage)
- Default locale is configurable in admin settings
- Date/number formatting respects locale

## Notes
- Use a flat key structure: `{ "nav.boards": "Boards", "nav.apps": "Apps", ... }`
- Keep translation keys semantic and grouped by feature
- Validation error messages from Zod should also be translatable
- ⚠️ Big Bang: string extraction touches many files

## Review Checklist
- [ ] All tasks completed
- [ ] Code follows project conventions
- [ ] No unintended side effects
- [ ] Build passes
- [ ] Tests pass (new + existing)

## Handoff to Next Phase
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